Unfortunately, cracking is pretty common in concrete, especially during the first 30 days, while itâs curing. There are a number of reasons why concrete cracks. The most common is because concrete shrinks as the excess water evaporates and it hardens. Concrete can also crack if it dries too quickly. Weather conditions â extreme temperatures, rapid temperature changes or conditions that are too wet or too dry â also play a major factor in how well concrete cures. When the width of a crack exceeds 1/4â in width, it is probably time to seek professional assistance.
Knot (unit) The knot (/nÉt/) is a unit of speed equal to one nautical mile (1.852 km) per hour, approximately 1.151 mph. The ISO Standard symbol for the knot is kn. The same symbol is preferred by the IEEE; kt is also common. The knot is a non-SI unit that is accepted for use with the SI.
Learn How to Convert Miles Per Hour to Knots Using our Conversion Formula. Converting a mile per hour speed measurement to a knot measurement involves multiplying your speed by the conversion ratio to find the result. A mile per hour is equal to 0.868976 knots, so to convert simply multiply by 0.868976. For example, 5mph = (5 Ã 0.868976) = 4.344881kn. Miles per hour and knots are both units used to measure speed. Learn more about speed and find more speed measurement conversion calculators. A mile per hour is an imperial measurement and can be abbreviated as mph, for example 1mph. A knot is an imperial measurement and can be abbreviated as kn, for example 1kn.